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The Bourne shell, also known as "sh", is a computer programming language developed by Stephen Bourne at AT&T's Bell Labs in 1979. It is a command processor typically run in a text window, allowing the user to type commands that cause actions. The Bourne shell was the first major Unix shell and introduced several programming features, including control flow and variables. It served as the standard Unix command line interpreter until it was largely superseded by Bash in 1989. This information can be verified from various sources including "A Quarter Century of UNIX" by Peter H. Salus and the official Bell Labs website.

Ask the right questions secure the right Bourne shell talent among an increasingly shrinking pool of talent.

First 20 minutes

General Bourne shell app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Bourne shell application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you define a variable in Bourne Shell?

In Bourne Shell, a variable can be defined using the syntax 'variable_name=value'. For example, 'x=10' defines a variable 'x' with value '10'. There should be no space around the '=' sign.

What are positional parameters in Bourne Shell?

Positional parameters are a series of special variables ($0 through $9) that contain the contents of the command line.

Describe the difference between 'echo' and 'printf' in Bourne Shell.

'echo' is a shell command that outputs its arguments followed by a newline. 'printf', on the other hand, is more sophisticated where you can format the output using format specifiers, similar to 'printf' in C language.

How would you execute a shell script in Bourne Shell?

A shell script can be executed by typing 'sh scriptname.sh' in the terminal. Alternatively, you can make the script executable using 'chmod +x scriptname.sh' and then run it using './scriptname.sh'.

What are the different types of variables in Bourne Shell?

In Bourne Shell, there are two types of variables: System variables and User-defined variables. System variables are created and maintained by the system, while User-defined variables are created and maintained by the user.

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What you’re looking for early on

Does the candidate have a strong understanding of Bourne shell scripting?

Did the candidate demonstrate problem-solving skills during the interview?

Has the candidate shown experience with Unix/Linux environments?

Has the candidate displayed good communication skills?

Next 20 minutes

Specific Bourne shell development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

Describe the difference between single and double quotes in Bourne Shell.

In Bourne Shell, single quotes preserve the literal value of all characters within the quotes, while double quotes preserve the literal value of all characters within the quotes, with the exception of '$', '`', '\', and '"', when preceded by the '$' sign.

How would you read input from the user in Bourne Shell?

Bourne Shell provides the 'read' command to read input from the user. For example, 'read name' will prompt the user to enter a value, which will then be assigned to the variable 'name'.

What are the different types of loops in Bourne Shell?

Bourne Shell supports three types of loops: for loop, while loop, and until loop.

Describe the difference between 'test' and '[ ]' in Bourne Shell.

In Bourne Shell, 'test' and '[ ]' are used for conditional testing. They are almost equivalent, but '[ ]' requires a space at both ends.

How would you handle errors in Bourne Shell?

Error handling in Bourne Shell can be done using 'trap' command. It allows you to catch signals and execute a command to handle the situation.

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At this point, a skilled Bourne shell engineer should demonstrate strong problem-solving abilities, proficiency in Bourne shell programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Bourne shell.

What does the following Bourne shell code do?
#!/bin/sh

if [ -d "$1" ]; then
  echo "Directory exists!"
else
  echo "Directory does not exist!"
fi
This script checks if a directory exists. If the directory exists, it prints 'Directory exists!', otherwise it prints 'Directory does not exist!'. The directory to check is provided as the first command line argument.
What will be the output of the following Bourne shell code?
#!/bin/sh

var1="Hello"
var2="World"

echo "$var1 $var2"
The output of this script will be 'Hello World'. It concatenates two variables with a space in between and prints them.
What does the following Bourne shell code do?
#!/bin/sh

arr=(1 2 3 4 5)

for i in "${arr[@]}"
do
  echo $i
done
This script prints all the elements of an array, one per line. The array contains the numbers 1 to 5.
What does the following Bourne shell code do?
#!/bin/sh

count_to_100 () {
  for i in {1..100}; do
    echo $i
  done
}

count_to_100 &

wait
This script defines a function that counts from 1 to 100, each number on a new line. It then runs this function in the background, and waits for it to finish before the script itself finishes.

Wrap-up questions

Final candidate for Bourne shell Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Bourne shell application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

What are the different types of parameter expansions in Bourne Shell?

Bourne Shell supports several types of parameter expansions, including: String length, Substring, Indirect variable reference, Default value, and Assignment with default value.

Describe the difference between '&&' and '||' in Bourne Shell.

In Bourne Shell, '&&' is a logical AND operator that performs command chaining, meaning the second command is executed only if the first command succeeds. '||', on the other hand, is a logical OR operator where the second command is executed only if the first command fails.

How would you debug a shell script in Bourne Shell?

You can debug a shell script in Bourne Shell by using the '-x' option with the shell command. For example, 'sh -x scriptname.sh'. This will print each command to the standard error output before executing it.

Bourne shell application related

Product Perfect's Bourne shell development capabilities

Beyond hiring for your Bourne shell engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Bourne shell projects, and can engage in multiple capacities.

Bourne shell Consultive assessments

Bourne shell Application Conversion Assessment Bourne shell Application Integration Assessment Bourne shell Data & Database Integration Assessment

Custom Bourne shell development projects

Custom Bourne shell App Conversion Bourne shell Custom App Development Process App UI Design for Bourne shell Facelifts

Hiring guide for Bourne shell Engineers

Bourne shell Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the Bourne shell engineer at this point.

Bourne shell Consultive assessments

Custom Bourne shell development projects